Hello, I just bought a 1975 Dodge W100 4WD. It came with a junk 318 in it, so I want to put my Mopar 400 in it. These motors came in these trucks, but I'm wondering if anyone knows what I might have to do in order to fit it in. Do I need new motor mounts or bell housings? What about the radiator, is it big enough to cool the 400?

I also want to lift the truck and put 36" tires underneath it. Anyone have any suggestions as to what the best way to do this on a 1975 is?

Thanks,

Zach

 

You will need to get the correct motor mount brackets from a Big Block truck, they are taller for a 4x4, also you will need a truck oil pan, cars will not work, the oil dip stick and tube from a truck. The best thing would be to find a donor truck thats a big block but they are getting hard to find nowadays. You also need all the pulleys and the powersteering bracket from a 4x4 bb truck, the car ones sit the p/s pump too low down into the front of the eng compartment, the rest of the car pulleys will work. The radiator will be sufficient for the 400, I used my old 318 radiator in my truck with a 440 swap and it never overheated. There are some wires going to the Alt that need to be lengthened some but I can't remember which ones they were?? The radiator will need to be looked at to see if the exit of the water pump lines up, some of the water pumps have the return side on the drivers side and some are on the pass side you will need to get one that matches you radiator, you can have the outlets swapped at a radiator shop if need be thats what I did. Also the exhaust manifolds you will need either headers or center dump from a bb pick up truck or motor home. As far as the lift, 2 choices all spring replacements of spring replacement for the front and blocks in the rear, pretty simple. Hope this helps................... ********Almost forgot you will need a big block trans also from a bb truck of bb bell housing if its manual. the internals are the same in the auto but the case is different

 

www.bouchillonperformance.com/ These people should everything you need, I think.

 

Thank you guys very much for the help. I appreciate it. I have a couple of questions still. The 400 ci motor was in a Dodge truck already, so I assume that I don''t need the oil pan, dip stick etc? However, the transmission in the truck is a 4 speed manual and it is connected to a 318. Do I need a different bell -housing? I thought that I could use the same tranny, but do I need a different tranny as well or just the bell housing, or neither?

Currently, the 400 is coupled to a 903 automatic transmission.

So i guess so far I need the motor mounts... could someone clarify what else for sure that I need?

Thank you very much guys,

Zach

 

You do need a bell housing.

 

Your in deep poop. Look at the rear of the crank on the 400. $5 says the pilot bushing hole is not finish machined. Used to be a bushing made that used the unfinished hole. Haven't seen one in years. Which leaves few choices, have one made or pull the crank and have it drilled.


The undrilled hole may not be deep enough to clear the end of the input shaft on the trans, so measure carefully and see if the shaft can be cut off and still leave enough to support the shaft in the bushing. BTW a 383 crank will bolt physically bolt in the 400, but the balance with the huge 400 pistons will be screwed.

All that aside, to mate a manual to a 400 requires a 400 specific flywheel,as they are externally balanced. Gonna be hard to find one,unless you can find one new someplace. 360s and 400s both are external, but the 360 isn't correct either. 383s/440 steel crank are internal balance. 440 cast crank is external,but not balanced properly for a 400 either.

How do I know this? Been there bought the shirt lol. Was about 19 yrs old at the time. Had the 400 crank drilled,put a 383 flywheel/4spd behind it, dropped it in a '70 Challenger. Vibrated like a bastard. Best bet for a big block is to find a 440 manual truck and rob the engine and all the parts.

 

how do you frigging know all this

 

ah. read whole post before replying

 

Man. This sounds like I'm going to run into alot more problems than I thought. Why is it that there are all these issues? I know dodge put the 400 in 1975 dodge w100's from the factory, did they not attach them to 4 speed trannies?

Thanks alot guys,

Zach

 

Makes a difference when one reads the complete post some times don't it? I'm guilty of the same at times. LOL